wireless control and send/recievе video data for car

[karpa-al]

Hello guys,
i'm new at this but i will not give up so there's some questions for you
I want to make a car that can be controlled in over 100-150 meters (through walls) , also i want to place a 8MPx web cam (or else I do not know what is suitable for a good picture on screen from mobile phone ) on it and some other features that i want to add in the car but they will be controlled with servos and/or electromagnets but the trick is that i want to control it from something like sony game cotroller with screen from Nokia N95 8G so i can see what the car can. Also i want to regulate the voltage on a DC motor for the wheels
 
Can you help me for the write choice of microcontroller and the type for connection between the car and remote controller (bluetooth or i don't know what else are out there)
and whatever you come up is welcome 

Thank you in advance!!!
p.s. sorry about my english

[Soeren]

Hi,

[...] i will not give up so there's some questions for you

That sentence is an oxymoron.

I want to make a car that can be controlled in over 100-150 meters (through walls) ,

Quite possible, just go ahead

also i want to place a 8MPx web cam

8Mpixel is way overdoing it and if you plan on getting real time video fed back, you have to forget it.

(or else I do not know what is suitable for a good picture on screen from mobile phone ) on it

A good picture is not just about pixels. Light is a more important factor and using more pixels that your cell phone screen has got is just a waste of time and bandwidth, as they cannot be shown and so the phone has to resize each picture to show them. 320 x 240 should be quite enough to drive a ROV around.

and some other features that i want to add in the car but they will be controlled with servos and/or electromagnets but the trick is that i want to control it from something like sony game cotroller with screen from Nokia N95 8G so i can see what the car can. Also i want to regulate the voltage on a DC motor for the wheels

Can you help me for the write choice of microcontroller and the type for connection between the car and remote controller (bluetooth or i don't know what else are out there)
and whatever you come up is welcome 

Sounds like a school project?
If I were you, I'd see if it's possible to get another assignment, as this sounds to be way over your head and it's not a small task you want to pull off.

[karpa-al]

i'm ashamed to tell that i'm 2nd year on electrotechnical faculty but they bother us with some abstract stuff's that are not helpful for this kind of thing's.
so i've decided to start with this on my own and learn through working. i'm familiar with constructing electronic circuit's and electromechanical stuff (i've already done it) but i'm beginner
in remote controling, transmiting/recieving data, and microcontrollers so i'm decided to do it with two colleagues
maybe i've overrated the camera it's possible to do it with 5MPx and the light i'm going solve with 5-6 led diodes from mobile ledflash
my basic question is about microcontrollers (can i build it because i'm financially short ) how can i connect it with my pc or gamecontroller , how can i transfer picture in real time ...
my first thought is to do it via bluetooth and controling it with pc but it will be more fun to do it with gamecontroller but like i said i'm new at this and asking you for help

[Soeren]

Hi,

maybe i've overrated the camera it's possible to do it with 5MPx

320x240=76.8kpixels should be enough for basic use and if the purpose is learning, the resolution shouldn't matter.
The more pixels you want to transfer, the fewer fps will be possible.

and the light i'm going solve with 5-6 led diodes from mobile ledflash

I don't think you realize how much cameras love light

my basic question is about microcontrollers (can i build it because i'm financially short ) how can i connect it with my pc or gamecontroller , how can i transfer picture in real time ...
my first thought is to do it via bluetooth and controling it with pc but it will be more fun to do it with gamecontroller but like i said i'm new at this and asking you for help

Yes, you can build a board with a microcontroller, but you'll need to use something like WiFi to get video across and you won't be able to get the controller to act upon the video, but that shouldn't be a problem if you just want visual feedback for a remote driver.

With WiFi, you could gt the video on a PC and then it would be more natural to control it from the PC as well. To send commands to the ROV, you could use a USB to serial adapter, or a USB experimenters board and control a transmitter with that.

[raptorwes]

I agree with Soeren about the camera, save money and bandwidth and go with a lower image quality. I have quite a few IP surveillance cameras and my VGA-640x480 (roughly .03 mp) cameras perform much better in lower light conditions than my 3mp cameras do and require a lot less bandwidth, granted the 3mp camera shows a lot more of the scene but it is at a much higher bandwidth cost.
I also notice that the high mp cameras will tend to go into night mode ( black and white)- if it has that feature- at a much higher lux that the vga cameras.   Here are some bandwidth figures --- 320x240 @30fps mpeg4  = about 648 Kbit/s ---    640x480 @30fps mpeg4 = about 2594 Kbit/s --- 1280x1024 @30fps mpeg4 = about 6641 Kbit/s ---  

[vinniewryan]

Wow, let me get in on this because I have a similar project where I need to transfer video over a network, but I hadn't yet considered video compression. Is there a chip that will auto-convert raw RGB data to mpeg4?

If I have a camera that's 640X480 pixels, RGB, 12 bit color data (4 bits per color), then effectively I need to be sending 368400 bits per frame (648 X 480 X 12). That means I can transmit 30 frames per second at less than 1.2Mhz data rate, but is this correct? I'm trying to look up how it's possible to get so much color data from 12 bits, I only see the ability to extract 16 levels of each color.

[karpa-al]

can i do all that with axon and control it with pc is there pin in on axon that alows to connect camera ?

[raptorwes]

vinniewryan
 I don't know of a specific chip that will do that for you because electronic engineering is not my forte. However, there are encoders that will take and analogue camera signal and do the encoding for you but they are typically pricey. Axis calls them camera servers http://www.axis.com/products/video/video_server/productguide.htm

karpa-al

I believe if you use a blackfin camera and a uart port on the axon you can connect the camera that way. I think you would also need to use another uart port for whatever wireless device you would use to transmit the data.. Maybe someone with more knowledge with the axon and wireless video can step in.

[vinniewryan]

Ah well, I may just write my own encoder/decoder, that way the video stream will be more private and harder to hack.

[Soeren]

Hi,

Is there a chip that will auto-convert raw RGB data to mpeg4?

I cannot give you a type number, but yes, either that or a chipset. They're used in cameras.

I'm trying to look up how it's possible to get so much color data from 12 bits, I only see the ability to extract 16 levels of each color.

You're right, but 16 levels of each, if blended can appear as a whole lot more (with well chosen palettes).

[vinniewryan]

Good point, I suppose using a more 'earthy' color palette would give a much better representation of an image than using the basic RGB shades. Thanks for the tip!